Bio Exam 1 review sheet answer key 2018 PDF

Preview

Summary

Exam 1 practice test key answers in red...

Description

BY#123#-0W# Exam#1#review#sheet# ! 1. One!atom!of!Na!can!combine!with!one!atom!of!Cl!(chlorine)!to!produce!one!molecule!of!NaCl! (table!salt).!! a. If!Cl!has!17!electrons!and!18!neutrons,!how!many!protons!does!Cl!have?!! 17! ! b. What!is!the!mass!number!of!Cl?! 35! ! c. If!Na!has!a!mass!number!of!23,!what!is!the!mass!number!of!NaCl?! 23!+!35!=!58! ! 2. If!you!wanted!to!combine!equal!numbers!of!Na!and!Cl!atoms!in!a!flask,!how!much!Cl!would!you! have!to!add!if!you!added!23!g!of!Na?!(Include!an!explanation!of!the!reasoning!behind!your! answer.)! 23!g!of!Na!is!equal!to!1!mole!of!Na.!A!mole!contains!6.02!x!1023!molecules!of!the!substance.!To! add!an!equal!number!of!molecules!of!Cl,!you!need!to!add!1!mole!of!Cl,!or!35!g.! ! 3. To!make!a!one-molar!(1!M)!solution!of!NaCl,!you!need!to!add!1!mol!of!NaCl!to!distilled!water!to! make!a!final!volume!of!1!L!(1,000!mL).!A!1!M!solution!is!said!to!have!a!molarity!of!1.!If!you! added!2!moles!of!NaCl!to!1!L!of!distilled!water,!you!would!make!a!2!M!solution!and!its!molarity! would!equal!2.!You!make!up!a!1!M!solution!of!NaCl.!! a. How!many!molecules!of!NaCl!are!in!the!1!M!NaCl!solution?! If!you!used!1!L!of!water!to!make!the!1!M!solution,!you!would!have!6.02!x!1023!molecules!in! the!liter.! ! b. How!many!molecules!of!NaCl!are!there!per!ml!of!solution?! To!calculate!the!number!of!molecules!per!ml,!divide!6.02!x!1023!by!1,000!=!6.02!x!1020! molecules/ml.! ! 4. What!is!the!pH!of!pure!water?!How!do!you!know!this?!! The!hydrogen!ion!concentration!of!pure!water!is!10-7.!! The!log10!of!10-7!is!-7.!The!negative!log10!of!10-7!is!therefore!+7.!SO,!pH!=!7.! ! (The!H+!ion!concentration!of!a!solution!can!be!represented!as!its!pH!value.!The!pH!of!a! solution!is!defined!as!the!negative!log10!of!the!hydrogen!ion!concentration.)! ! 5. One!of!the!buffers!that!contribute!to!pH!stability!in!human!blood!is!carbonic!acid!(H2CO3).! Carbonic!acid!is!a!weak!acid!that!dissociates!into!bicarbonate!ion!(HCO3-)!and!a!hydrogen!ion! (H+).!Thus,!H2CO3!ßà!HCO3-!+!H+!! If!the!pH!of!the!blood!drops,!one!would!expect:!! If!the!pH!drops,!expect!for!the!reaction!to!proceed!to!the!left!with!the!base!(HCO3-)!removing! the!hydrogen!ions!(H+)!and!forming!carbonic!acid!(H2CO3).! ! !

6. Explain!mechanisms!that!regulate!membrane!fluidity!based!on!environmental!temperature?! For!example,!how!do!animals!keep!membranes!fluids!in!very!low!temperatures?!! Increasing!the!concentration!of!unsaturated!phospholipids!during!the!cold!months!to!keep! membranes!fluid!at!lower!temperatures.!Also,!addition!of!cholesterol!into!the!membrane!will! hinder!the!solidification!by!distrupting!the!regular!packing!of!the!phospholipids.!!! ! 7. What!happens!to!red!blood!cells!(RBCs)!when!you!place!them!in!a!! a. hypertonic!solution?! Cells!will!shrivel!due!to!the!excess!solutes!in!the!solution!and!water!rushing!out!of!the! cell.! ! b. hypotonic!solution?! Cells!will!burst!due!to!more!solutes!being!inside!the!cell!and!water!will!rush!into!the! cell!causing!them!to!burst.!! ! 8. Explain!how!simple!diffusion!applies!to!breathing!and!exhaling.!Is!energy!required?!Why!or! why!not?!(You!can!use!a!drawing!if!that!helps!you!explain!it!fully!)! Concentration!gradients!–!O2!levels!are!higher!in!the!inhalation!air!compared!to!O2!levels! inside!the!gas!exchange!cells,!so!O2!easily!diffuses!into!these!cells.!Alternatively,!CO2!levels! are!higher!inside!the!gas!exchange!cells!compared!to!outside,!so!CO2!easily!diffuses!into!the! air!that!is!then!exhaled.!! ! 9. A!marathon!runner!has!just!arrived!in!the!emergency!room!with!severe!dehydration,!and!the! physician!must!decide!which!type!of!solution!to!pump!into!her!veins:!pure!water,!0.9!percent! saline,!or!1.5!percent!saline.!Blood!cells!are!approximately!0.9!percent!saline.!Describe!what! is!likely!to!happen!to!the!blood!cells!when!they!are!exposed!to!each!solution!(using! descriptions!of!tonicity).!Which!solution!should!the!runner!be!given!and!why?!! In!pure!water,!the!blood!cells!will!take!on!water!through!osmosis,!swell,!and!eventually! rupture.!In!0.9%!saline,!the!cells!should!neither!gain!nor!lose!a!significant!amount!of!water.! In!a!1.5%!saline!solution,!the!cells!should!lose!water!and!shrivel.!In!order!to!rehydrate!the! runner,!a!solution!isotonic!to!the!patient’s!blood!cells,!0.9%,!should!be!infused!into!her!blood! stream.!! ! 10. Consider!a!fragment!of!DNA!that!has!a!total!of!10!base!pairs.!Four!of!these!contain!adenine! and!six!contain!guanine.!How!many!hydrogen!bonds!would!there!be!in!this!fragment! between!purine/pyrimidine!pairs?! A:T!–!2!bonds;!C:G!–!3!bonds!! (4*2)!+!(6*3)!=!26! ! 11. Is!glucose!uptake!in!intestinal!cells!passive!or!active?!What!information!do!you!need!to!know! to!answer!this!question?!! What!you!need!to!know:!1)!what!are!the!glucose!concentrations!inside!and!outside!the!cell?! 2)!can!glucose!cross!the!membrane!alone!or!does!it!need!assistance?!! Information:!If!glucose!concentration!is!higher!inside!the!cells!compared!to!outside!(lumen! of!intestine)!then!glucose!must!be!taken!up!across!it’s!gradient!requiring!energy.!However,!if! the!concentration!of!glucose!is!lower!inside!the!cell!compared!to!the!lumen,!then!passive! diffusion!with!the!gradient!will!be!used.!! !

12. In!symbiotic!relationships,!each!organism!provides!the!other!with!something.!Use!your! knowledge!of!organelle!function!to!suggest!what!the!original!chloroplast!and!mitochondrial! symbionts!might!have!provided!for!and!received!from!the!host!eukaryotic!cell.! Both!mitochondria!and!chloroplasts!are!involved!in!energy!transformations!and!could!have! provided!ATP!or!other!high-energy!compounds!to!a!host!cell.!They!could!have!received! protection,!specialized!proteins,!and/or!a!unique!environment!from!their!host.!! ! 13. Explain!how!transport!of!each!molecule!(a,!B,!C,!and!D)!in!the!diagram!below.!Make!sure!to! pay!attention!to!the!directions!of!transport!as!shown!by!the!arrows.!(Relative!size!of!the! molecules!is!represented!by!the!size!of!the!letter.!The!concentrations!of!molecules!on!each! side!of!the!molecules!can!be!determined!by!the!numbers!of!each!letter!on!each!side!of!the! B B B C B B B B C C B C C B C C B Ca CB B B B C BB C B B B C C C B B a C B B CB C B B C C C a CBC C a B C a B B B a B B Ca B Ba B Ba B B

D

D

a a a

a

B

a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a

C aa B a a a

D

a a

a

aa

a C aa B a a C

C

B C

C

C

B

C

B

C

C

B

membrane.)! a:!simple!passive!diffusion!across!the!membrane.!a!is!a!small!diffusible!molecule!that!doesn’t! require!assisted!transport.! B:!passive,!facilitated!(use!of!a!transporter)!diffusion!with!gradient.!No!energy!required.! C:!active,!facilitated!(use!of!a!transporter)!diffusion!against!gradient.!Energy!required.! D:!Unable!to!diffuse.!Too!big!and!no!transporter!present.!! ! 14. The!role!of!a!certain!cell!in!an!organism!is!to!secrete!a!particular!protein.!Create!a!flow!chart! in!which!you!trace!the!production!of!that!protein!form!the!nucleus!through!all!of!the! necessary!organelles!to!the!point!of!release!from!the!cell.!! DNA!coding!for!particular!protein!is!transcribed!into!mRNA.!! mRNA!is!transported!to!ribosomes!located!on!RER!where!protein!translation!occurs.!! Protein!is!transported!by!vesicle!to!golgi!where!packaging!and!modifications!occur.!! Vesicle!transports!packaged!protein!to!cell!membrane!where!it!is!secreted!into!the! periphery.! ! 15. List!the!type!of!macromolecular!class!of!biological!molecule!for!each!structure:! (you!might!want!to!list!the!four!macromolecules!here:!_CHO______,!___protein____,!___lipid_____,! __nucleic!acid____!

__NA!-!cytosine_!!! !

!

___CHO-disaccharide_!

!!! !

!! !

!!!!!!!__protein!-!AA_!!

!!__NA-thymine__!!!!!

!!!!! !

!!! !

!!! ! ! ! ! ! !

__lipid!–!vit!A__!

!!!!!!!__protein!-!AA___!!!

!!__CHO!-!polysaccharide__!

__lipid!-!steroid___!!!!!!!

!!!__!CHO!-!sugar!__!!!

!!!___CHO!-!sugar___!

___lipid!-!FA___!...